iotests: add test 178 for qemu-img measure

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-10-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
4 files changed